See a separate Haskell Wiki page on it. Daan Leijen's original HaskellDB, and an updated version that works with current Haskell implementations and is relatively platform-independent. HaskellDB is a combinator library for expressing queries and other operations on relational databases in a type safe and declarative way. All the queries and operations are completely expressed within Haskell, no embedded (SQL) commands are needed. This close integration makes it possible to do arbitrary computations on the database (like computing the transitive closure).

HaSQL is a Haskell to ODBC interface. HaSQL allows Haskell program to run SQL queries against an ODBC compliant database. Queries with parameters are supported. Data is retrieved from the database as a lazy list.

VooDooM reads VDM-SL specifications and applies transformation rules to the datatypes that are defined in them to obtain a relational representation for these datatypes. The relational representation can be exported as VDM-SL datatypes (inserted back into the original specification) or SQL table definitions (which can be fed to a relational DBMS)